Mastering Mental Math with Decimals

Why is mental math important for adding and subtracting decimals?

• It allows you to work things out much faster.

• It helps you remember numbers.

• It makes you better at multiplication.

• It helps you write faster.

What is the result of 12 + 3.04 + 8.28 using mental math?

• 23.28

• 23.32

• 23.40

• 23.04

In addition, why does the order of adding numbers not matter?

• Because addition is reflexive.

• Because addition is distributive.

• Because addition is associative.

• Because addition is commutative.

How can you simplify 6.97 + 4.15 using mental math?

• By adding 6 and 4, then 0.97 and 0.15 separately.

• By dividing 6 by 4, then adding 0.97 and 0.15.

• By subtracting 4 from 6, then adding 0.97 and 0.15.

• By multiplying 6 and 4, then adding 0.97 and 0.15.

What is the result of 6.97 + 4.15 using the technique of removing the decimal point?

• 11.12

• 10.12

• 10.32

• 11.32

What is the result of 9.04 - 6.98 using estimation?

• 2.02

• 2.06

• 2.04

• 2.00

How can you simplify 9.04 - 6.98 using mental math?

• By dividing 9 by 7, then adjusting for the decimals.

• By multiplying 9 and 7, then adjusting for the decimals.

• By adding 9 and 7, then subtracting the decimals.

• By estimating 9 - 7 and adjusting for the decimals.

What is the result of 9.04 - 6.98 using the balancing technique?

• 2.06

• 2.02

• 2.00

• 2.04

Why is it important to practice mental math for adding and subtracting decimals?

• To become faster and more accurate.

• To enhance multiplication skills.

• To remember numbers better.

• To improve writing speed.

What is the result of 48 + 19 + 2 using mental math?

• 69

• 68

• 70

• 71